In general, a refrigerator is an apparatus for keeping foods frozen or at a temperature slightly above freezing by discharging cold air generated by a refrigeration cycle, realized using, for example, a compressor, a condenser, an expansion valve, and an evaporator, to lower the temperature in a storage compartment thereof.
A typical refrigerator includes a freezing compartment, in which foods or beverages are kept frozen, and a refrigerating compartment, in which foods or beverages are kept cold.
There are several kinds of refrigerators, including a top-mounting type refrigerator, in which a freezing compartment is located above a refrigerating compartment, a bottom-freezer type refrigerator, in which a freezing compartment is located below a refrigerating compartment, and a side-by-side type refrigerator, in which a freezing compartment and a refrigerating compartment are respectively located on left and right sides. The freezing compartment and the refrigerating compartment may be provided with respective doors, and may be accessed through the respective doors.
In addition to such refrigerators, which include a refrigerating compartment and a freezing compartment which are compartmentalized from each other, there is also a refrigerator which allows access to both the refrigerating compartment and the freezing compartment through a single door. This kind of refrigerator is mostly small-sized, and is typically constructed such that the freezing compartment is provided in a predetermined space within the refrigerating compartment.
Among the top-mounting refrigerators, there is also provided a French type refrigerator in which an upper refrigerating compartment is opened and closed by right and left doors. The freezing compartment of the French type refrigerator may also be opened and closed by right and left doors.
Recently, in addition to the original function of keeping foods refrigerated or frozen, the variety of functions provided by refrigerators is increasing. Specifically, a dispenser is installed to a door of the refrigerator so as to provide purified water and ice, and a display is installed on the front surface of the door so as to show the state of the refrigerator and to assist a user in controlling the refrigerator.
In recent years, a refrigerator in which only part of a storage compartment is separately openable has been proposed. Specifically, in addition to a main door for opening or closing a storage compartment, a refrigerator which is provided with a sub door for opening or closing a sub storage compartment defined in the main door has been proposed. The sub storage compartment is a portion of the space in the main storage compartment, and is isolated from the main storage compartment by a partition wall. This kind of refrigerator may be referred to as a door-in-door (DID) refrigerator or a dual-door refrigerator. This DID refrigerator is advantageous in that the outward leakage of cold air from the main storage compartment is considerably reduced when only the sub door is opened.
For example, stored objects, such as beverages, which are frequently taken out of and put back into the storage compartment, are stored in the sub storage compartment, and thus the sub storage compartment can be accessed by opening the sub door while maintaining the main door in the closed state.
This kind of DID refrigerator or dual-door refrigerator may be configured in such a manner that a sub door is embedded in a main door. In other words, the sub door is disposed so as to cover the front surface of the main door, and the main door has a front surface area that is substantially the same as that of the front surface of the sub door.
In this kind of DID refrigerator, the sum of the thickness of the main door and the thickness of the sub door may be the same as, for example, the thickness of a right refrigerating compartment door. Each of the main door and the sub door has a relatively small thickness.
The present applicant has proposed a refrigerator, which is provided with a DID door in which a sub door is embedded in a main door, in Korean Patent Application No. 10-2015-0088477 (hereinafter, referred to as “related patent”). An example of this kind of refrigerator is illustrated in FIG. 1.
As illustrated in FIG. 1, a right refrigerating compartment door 25 includes a main door 100, which is hingedly coupled to a body 10 and which has an opening 116 formed in the center region thereof, and a sub door 200, which is hingedly coupled to the main door 100 so as to be fitted into the main door 100. A sub storage compartment opening 115 may be provided inside the opening 116 so as to allow a user to access a sub storage compartment provided behind the main door 100. In the related patent, the sub storage compartment opening 115 may be configured to define a window, which allows the storage compartment to be visible from the outside.
The sub door 200 is configured to be smaller than the main door 100, and is fitted in the opening 116 of the main door 100 when the sub door 200 is closed. Specifically, at least part of the anteroposterior thickness of the sub door 200 is accommodated in the main door 100. In other words, at least part of the side surface of the sub door 200 is fitted into the opening 116 in the main door 100. The front surface of the sub door 200 may be preferably flush with the front surface of the main door 100 (specifically, the front surface of the portion of the main door 100 that surrounds the sub door 200).
Accordingly, the refrigerator illustrated in FIG. 1 may be considered as a refrigerator in which the sub door 200 is fitted into the main door 100 so as to close the opening 116 of the main door 100 in the state in which the main door 100 is closed. This refrigerator may be referred to as an inside-type DID refrigerator or an inside-type dual-door refrigerator. Meanwhile, a conventional general refrigerator, which has been described above, may be referred to as an outside-type DID refrigerator or an outside-type dual refrigerator.
In the inside-type DID refrigerator illustrated in FIG. 1, since the sub door 200 is embedded in the main door 100, the thickness of the sub door 200 may be further increased compared to the outside-type DID refrigerator. In other words, increasing in the thickness of a thermal insulation wall means reducing the loss of cold air.
However, since part of the sub door 200 is always fitted in the main door 100 even when the sub door 200 is opened, a problem occurs in that it is difficult to open the sub door 200 to an angle exceeding 90 degrees. The reason for this is because interference between the main door 100 and the sub door 200 occurs when the sub door 200 is opened beyond 90 degrees.
Furthermore, the refrigerator disclosed in the related patent enables the inside of the storage compartment 11 to be visible from the outside through the sub door 200. Specifically, the refrigerator enables the storage compartment 11 to be visible without having to open the sub door 200 from the outside by providing the sub door 200 with a plurality of transparent panels. Here, the plurality of transparent panels are provided in order to satisfy the thermal insulation requirement and to enable the inside to be visible from the outside.
However, since the weight of the sub door 200 itself is relatively increased, a problem may occur in that a hinge, which is adapted to allow the sub door 200 to be rotated thereabout, becomes deformed. In other words, since the sub door 200 may droop when it is used for an extended period of time, there may be a problem in that the sub door 200 is not normally fitted into the main door 100.